衰亡期黑藻与生长期菹草交替生长对水体磷迁移的影响

为利用冷暖种交替控制水体磷污染、抑制水体富营养化,揭示湖泊演化规律和机理。研究设置单季植物组(黑藻组、菹草组)和交替生长组(黑藻组+菹草组)进行实验。交替生长组在黑藻衰亡期种植菹草,监测各组上覆水和底泥中各形态磷含量的变化,计算黑藻衰亡释放磷及菹草生长吸收磷的总量,同时测定环境因子指标。分析沉水植物交替生长(黑藻+菹草)过程对衰亡期沉水植物(黑藻组)释放磷所带来的二次污染的消减作用,并分析环境因子变化与磷含量之间的关系。实验结果表明:黑藻+菹草组显著(P<0.05)降低了上覆水中总磷(TP)、溶解性总磷(DTP)和溶解性活性磷(SRP)的浓度;显著(P<0.05)降低了间隙水中DTP和SRP的浓度。底泥TP含量黑藻组呈上升趋势,黑藻+菹草和菹草组呈下降趋势。在采用菹草生物量期望2倍于衰亡植物黑藻生物量的模拟实验条件下,每实验组沉水植物黑藻衰亡分解所释放的磷为1.51 g,沉水植物菹草生长所富集吸收的磷为1.83 g。因此,菹草具备消减黑藻所释放磷的能力,可作为冷暖种交替控制水体富营养化的备选物种。实验组磷的迁移方向分别为:黑藻组磷迁移最终方向为底泥,黑藻+菹草组和菹草组磷的迁移方向为植物。黑藻+菹草组通过提高环境中DO和ORP,使得水相中磷向沉积物相中迁移,从而使得水相中各形态磷浓度保持在相对较低的水平。

Effects of alternating growth of declining H.verticillata and growing P.crispus on phosphorus migration in water

In order to reveal the mechanism of alternating aquatic plants cold and warm species to control phosphorus pollution and eutrophication,submerged macrophyte P.crispus and H.verticillate were planted respectively as single season plant groups,and H.Verticillata+P.crispus were planted as alternate growth process in this study.Phosphorus concentration in overlying water and sediment was monitored.The amount of phosphorus released from the decomposition of H.verticillate and the total phosphorus uptake by P.crispus were calculated.The environmental factors were determined simultaneously.The subtractive effects of alternate growth of submerged macrophytes(H.Verticillata+P.crispus)on the release of phosphorus from submerged submerged macrophyte(H.Verticillata)and the relationship between the changes of environmental factors and the content of phosphorus were analyzed.The results indicated that H.Verticillata+P.crispus groups significantly reduced total phosphorus(TP),dissolved total phosphorus(DTP)and soluble reactive phosphorus(SRP)concentration of the overlying water and DTP and SRP concentration of the interstitial water(P<0.05).The content of TP in sediment increased in H.Verticillata,but decreased in H.Verticillata+P.crispus and P.crispus groups.Phosphorus release from the H.Verticillata decomposition in each experiment group was 1.51 g,and the phosphorus uptake by the submerged plant P.crispus was 1.83 g under the simulated experiment which P.crispus expected biomass was double as much as decomposing plant H.Verticillata biomass.Therefore,P.crispus had the ability to reduce phosphorus release from H.Verticillata.The transfer direction of phosphorus in the experimental group showed that the final direction of phosphorus transfer in the H.Verticillata group was sediment,while in the H.Verticillata+P.crispus and P.crispus was plant.This could be explained by the high DO and ORP.In the groups H.Verticillata+P.crispus phosphorus transferred from water to sediment by increasing DO and ORP.